Dear Editor,

A 58-year-old woman presented with massive nodulous lesions on her hands and feet in our outpatient clinic in spring 2018. She had a history of seropositive erosive rheumatoid arthritis (RA) starting in 2005 with first nodules appearing in 2008. The patient had received sequential treatments with prednisolone, methotrexate 15 mg/week for 4 years and stopped in 2012, leflunomide for 3 years and adalimumab until presentation. Over the years, hand and feet nodules worsened impairing her function. She also developed skin lesions around the nodules leading to severe recurrent local infections requiring surgical removal of some of the nodules, ultimately necessitating the amputation of two digits. At presentation, the patient showed massive nodular deformations and palpable subcutaneous soft nodules, some of which emptied spontaneously (figure 1A). MRI showed pronounced and widespread soft tissue deposits in her right hand with virtually complete disappearance of the physiological joint surfaces in the absence of active synovialitis and a carpal collapse with complete destruction of the os lunatum, partial destruction of the os scaphoideum and os triquetrum (figure 1C). A dual-energy-CT did not show any deposition of uric acid crystals.

Incisional biopsy specimens of the affected tissue showed extensive confluent amorphous necrosis surrounded by palisade-like histiocytes, epitheloid and Langhans cells, as well as fibrosclerotic connective tissue with dense lymphoplasma infiltrates, resembling a rheumatoid nodule. Ziehl Neelsen stain, M. tuberculosis culture and PCR were negative. In combination with antibiotic treatment to control local infection, which was resolved within 10 days, we started treatment with the JAK Inhibitor baricitinib (4 mg/day). At 2-year follow-up, nodules substantially regressed upon treatment with baricitinib and no further infection occurred (figure 1B).

Rheumatoid nodules are associated with seropositive RA and found in a subset of RA patients, usually in those with severe disease. Some treatments for RA, such as methotrexate, leflunomide, tumour necrosis factor and interleukin-6 receptor inhibitors can paradoxically enhance nodule growth.^1–5 While rheumatoid nodule formation is usually mild, it occasionally can be severe. In this patient, nodule formation was excessive, highly destructive and life threatening due to the associated soft tissue infections.

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Figure 1

Massive nodular deformations and palpable subcutaneous soft nodules (A). At 2-year follow-up, nodules substantially regressed upon treatment with baricitinib (C). MRI right hand with pronounced and widespread soft tissue deposits (B).